LTC1400
Complete SO-8, 12-Bit,
400ksps ADC with Shutdown
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FEATURES
DESCRIPTION
The LTC®1400 is a complete 400ksps, 12-bit A/D con-
verterwhichdrawsonly75mWfroma5Vor± 5Vsupplies.
This easy-to-use device comes complete with a 200ns
sample-and-hold and a precision reference. Unipolar and
bipolar conversion modes add to the flexibility of the ADC.
The LTC1400 has two power saving modes: Nap and
Sleep. In Nap mode, it consumes only 6mW of power and
can wake up and convert immediately. In the Sleep mode,
it consumes 30µW of power typically. Upon power-up
from Sleep mode, a reference ready (REFRDY) signal is
available in the serial data word to indicate that the
reference has settled and the chip is ready to convert.
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Complete 12-Bit ADC in SO-8
Single Supply 5V or ±5V Operation
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Sample Rate: 400ksps
Power Dissipation: 75mW (Typ)
72dB S/(N + D) and –80dB THD at Nyquist
No Missing Codes over Temperature
Nap Mode with Instant Wake-Up: 6mW
Sleep Mode: 30µW
High Impedance Analog Input
Input Range (1mV/LSB): 0V to 4.096 or ± 2.048V
Internal Reference Can Be Overdriven Externally
3-Wire Interface to DSPs and Processors (SPI and
MICROWIRETM Compatible)
The LTC1400 converts 0V to 4.096V unipolar inputs from
a single 5V supply and ±2.048V bipolar inputs from ±5V
supplies. Maximum DC specs include ±1LSB INL, ±1LSB
DNLand45ppm/°Cdriftovertemperature. GuaranteedAC
performance includes 70dB S/(N + D) and –76dB THD at
an input frequency of 100kHz, over temperature.
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APPLICATIONS
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High Speed Data Acquisition
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Digital Signal Processing
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Multiplexed Data Acquisition Systems
Audio and Telecom Processing
Digital Radio
Spectrum Analysis
Low Power and Battery-Operated Systems
Handheld or Portable Instruments
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The 3-wire serial port allows compact and efficient data
transfertoawiderangeofmicroprocessors,microcontrollers
and DSPs.
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, LTC and LT are registered trademarks of Linear Technology Corporation.
MICROWIRE is a trademark of National Semiconductor Corp.
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TYPICAL APPLICATION
Power Consumption vs Sample Rate
Single 5V Supply, 400kHz, 12-Bit Sampling A/D Converter
100
5V
1
8
NORMAL CONVERSION
10
V
V
SS
CC
+
10µF
0.1µF
NAP MODE
BETWEEN CONVERSION
1
MPU
P1.4
LTC1400
2
7
ANALOG INPUT
(0V TO 4.096V)
A
V
CONV
CLK
IN
SLEEP AND NAP MODE
3
4
6
5
2.42V REF
P1.3
P1.2
REF
OUT
0.1
0.01
BETWEEN CONVERSION
+
GND
D
SLEEP MODE BETWEEN
CONVERSION
10µF
0.1µF
OUT
SERIAL
DATA LINK
LTC1400 • TA01
6.4MHz CLOCK
0.001
100
SAMPLE RATE (Hz)
0.01 0.1
1
10
1k 10k 100k 1M
LTC1400 • TA02
1